A power transmission device includes: a power transmission coil to transmit electric power to a power receiving coil by an electromagnetic induction method; a driving unit to supply a driving voltage to the power transmission coil; a detection unit to detect an electric current flowing in the power transmission coil based on the driving voltage; a control unit to change an amplitude of the driving voltage; a starting point detection unit to detect the amplitude of the driving voltage as a characteristic point at which an electric current starts to flow in the power receiving coil, on a characteristic line representing a relationship between the driving voltage supplied to the power transmission coil and the electric current detected by the detection unit; and a transmission stopping control unit to stop power transmission by the power transmission coil if the characteristic point is not detected by the starting point detection unit.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A power transmission device, comprising: a power transmission coil which transmits electric power to a power receiving coil by an electromagnetic induction method; a driving unit which supplies a driving voltage to the power transmission coil; a detection unit which detects an amplitude of an electric current flowing in the power transmission coil based on the driving voltage supplied by the driving unit; a control unit which changes an amplitude of the driving voltage supplied by the driving unit; a characteristic determining unit which determines whether the amplitude of the electric current detected by the detection unit is increased at a constant rate when the control unit gradually increases the amplitude of the driving voltage supplied to the power transmission coil from a minimum value; and a transmission stopping control unit which stops power transmission by the power transmission coil if the characteristic determining unit determines that the amplitude of the electric current is increased at a constant rate.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
November 16, 2009
September 4, 2012
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